The US Visitor and Immigrant Status Indicator Technology (US-VISIT) program provides visa-issuing posts and ports of entry with the biometric technology that enables the US government to establish and verify the identity of foreign nationals who apply for visas and enter the US. The biometrics are collected to verify that the person at the port of entry is the same person who received the visa. Immigration officials use this information to help them make visa-issuance and admission decisions as part of the visa application process or entry inspection.
Procedures involve digital photographing and inkless fingerprinting. More details are available on the US Department of Homeland Security (DHS) US-VISIT webpage.